Reliable  data transfer  over a perfectly reliable channel rdt 1.0

First  all consider  the simplest  care in  which  the underlying  channel  perfectly reliable.  The protocols  itself  which in  trivia. The finite state  machine  definition for  the rdt 1.0 sender  and receiver are shown  in the FSM  in  defines the  operation of the sender while  the s FSM  defines the operation  of the  defines receiver. It is important  to note  that  there are separate FSM  for the  sender  and  of the receiver. The sender an deceiver FSM in figure  each have just  one  state. The  arrows  in the FSM  description indicate the transition of the protocols from one  state to another. The event causing the transition is shown above  the horizontal line  labelling the transition and the  actions  taken  when the  event occurs are shown below  the horizontal  lien when  no action  is taken  on an event  or no event  occurs   and an  action is  taken we  use the symbol a below or above the horizontal respectively  to explicitly denote the lack  of an action or event. The  initial  state of the FSM  is indicated by the  dashed arrow.

                               Figure  rdt a protocol for a completely  reliable  channel

The sending  side of rdt  simply  accepts  data from  the upper  layer via the rdt send  event,  creates a packet  containing the data   and sends  the packet into the channel. The rdt send event would  result form  procedure call  by the upper layer  application.

On the receiving  side  rdt receives  a packet  from the  underlying channel via the rdt _rev event removes tha data from the  packet and passes the data  up to the upper layer. The  rdt_ rcv event would  result  from a procedure call  event from the lower layer  protocols.

In  this protocols  there  is no  difference  between a unit  of  data  and  a packet. Also  all packet  flow is  from  the sender  to receiver with a  perfectly  reliable  channel  there  is no  need for the  receiver  side to provide  any feedback to the sender.